Artificial hand



Nov. 20, 1934. F. c. HENNING ARTIFICIAL HAND Filed Jan. 26, 1952 2 Sheets-Sheet l Nov. 20, 1934. F. c. HENNING 1,981,693

ARTIFICIAL HAND Filed Jan 26, 1932 2 Sheets-Sheet 2 Patented Nov. 20, 1934 umrso's-rArss PATENT OFFICE j mamm l. HAND Frederick Charles Henning, Chicago,

Application January 26,

--.the case may be. When the spring serves merely to open the hand, it may becomparatively light 6 Claims.

grip that is-firmwhile being cushionedat the points of contact between "the digits and the object that is beingheld. I Y

In carrying out my invention, I employ ahollow palm member to which are hinged a thumb and fingers preferably composed of soft rubber; the four fingers beingpreferablymoulded ina single unit so that all of thefingers may be connected to the palm deviceby a' single fastening. The fingers and thumb are supported for swinging movements from and toward each other about parallel axes. By making the thumb and fingers of soft rubber, they will yield when closing upon an object; thereby not only avoiding the danger of marringthe object with the finger but providing a grip that is much more secure than is the case where the fingers are of hardfmaterial. Rubber that is sufiiciently soft to give the yielding character to the grip of the hand'i's" not stifi enough to permit the hand to carry'heavy weights or' to resist other powerful forces tending to open the hand. I, therefore, incorporate in the thumb and fingers stiff reenforcing elements that extend lengthwise through the same; The reenforcing elements preferably extend from the knuckles to within a short distance of the tips of the fingers and thumhso that a short section at the tip end of each finger and thumb consists of rubber only. Therefore, when the finger tips are pressed against an object; they yield much in, the same manner as the tips of the fingers of-a human hand, even though the fingers as a whole remain substantially rigid. v

It is not enough that the thumb and fingers be so constructed that they may take a firm cushioned grip, but means mustbe provided for exerting a strong closing pressure on the thumb and Artificial hands are commonly closed fingers. in either of two ways; some hands being closed by a spring and being opened by a pull exerted upon the hand through a suitable pull cord; and other artificial, hands being normally held open by a springand being closed by. means of a pull cord. My. improved hand is adapted'to be operated'in either of these two ways, .a strong clock spring being utilized for-opening or closing the hand,.as

.nection with th .wherein: 1 l

1932, Serial no sssmz spring-whereas, when the grip of the'hand'is de- 'terminedlby the strength of the spring, a comparativelypowerful clock spring must be employed. 'The mechanism which I have devised for opening and closing the fingers is such that it is only necessary to reversethe direction in which ,pthe pull cord leaves a wheel'or disk and substitute a different clock spring reversely connected to the wheel or disk, in order to change the hand from one type toanother. The power for moving the fingers and thumb is applied to the disk or this power 'isidelivered to the actuating arms or levers forthe thumb and'fingers from points near the periphery of the disk orwheel.

Thevarious features of novelty whereby my invention is characterized will hereinafter be pointed out with particularity in the claims; but, for a full understanding of my invention and of its objects and advantages, reference may be had to the following detailed description taken in conaccompanying drawings,

Figure 1 is a top plan view of a hand constructed in accordance withmy'inv'ention, the cover plate on the back of the hand being removed; Fig. 2 is a section on line 22 of Fig. 1 showing, in dotted lines, the manner in which the third finger on the hand may be flexed independently of the other fingers; Fig-3- is'a section 'on line 3-3 of Fig. 2; Fig. 4 is a longitudinal section through the base or knuckle end of thethumb; Fig. 5 is a section on line 55 of Fig. 2 Fig. 6 is a section on line 66 of Fig. 5; Fig; 7 is an elevational view showing only a small fragment of the-hand looking in the direction of the arrow underneath Fig.

whereas the spring holds the hand open when free to do so,.in Figs. 1-7.

Referring to the drawings, 1 represents what may be termed a hollow palm or body portion of Y the hand. The member '1' is open at the front edge and, at one side; has a thumb opening. The thumb 2 is preferably madefof a body of soft rubber. moulded about a 'reenforci'ng bar 3. This wheel at or near theperiphery of the latter, and

on the member; 12.

bar is preferably a flat, more or less resilient bar set on edge, as shown in Fig. 2. The rubber extends a short distance beyond the tip of the bar, so that the tip of the thumb is comparatively yieldable. A tubular member 4 passes transversely through and is fixed to the bar at the base end or knuckle of the thumb; this member 4 serving as a long bearing to receive a pin 5 extending transversely through the=thumb and into :stationary parts of the hand device on opposite sides of the thumb. In other words, the thumb may swing about the pin 5 as an axis. The reenforcing bar extends rearwardly to and beyond the rear end of the thumb to provide an operatingarm .6 that extends up into the interior of the hollow palm device.

The four fingers 7, 8, 9 and 10, arepreferably moulded as part of a single-block-or-unit;being connected together at their bases or knuckles-b a part 11 extending across all four fingers. Moulded, within the. part 11 is a long tube: 12. extending, transversely of the. fingers. Each finger contains -a reenforcing1bargsimilar" to the bar13;

these bars being, indicated; at 13, 14, 15.:and 16. All of these barsextend fromrthe-tubular member 12 to points a shortdistance removed from the extreme tips of the correspondingifingers. If the bars in the. fingers; are-fixedto; the tubular member, the fingers-will. allrbe held in: fixed relation to each other exceptasthey ma-yyield more or less sidewise due to the resiliency of the fiat bars. It may sometimes-be ,desirable. to inserta pen, pencil or fork or spoon handle betweentwo'of the fingers before the'hand isclosed upon the article. Thiswould not be possible if the fingers were held in rigid relation to, each other. Therefore, in the arrangement shown, thebars in all of the fingers except the third fingereare fixed to the member 12,whereas the bar 15, in the third finger, is loose on the member. 12 8018.5 to'be capableof swinging about the latter. In order: that. the third finger will not be vpermittedgto wobblesidewise, I

or the like 28. A pin 29 extends down through the top of the pedestal and through the shaft to hold the latter against rotary or endwise movements. The side wall of the hollow palm device opposite that in which one end of the shaft 26 is supported contains an opening 30 through which may be inserted a key (not shown) for turning the shaft 26. Surrounding the shaft 26, between the pedestal and the disk or wheel, is a spiral clock spring 31, one end of which is fixed to the shaft and the other end of which is connected to the disk or wheel. In the arrangement .:'shown, the spring is housed in a cup-shaped casing 32, one end of the spring extending through a slot in the periphery of the casing and being Lbent .around a pin or stud 33 projecting laterallyirom the disk or wheel. The spring,

therefore, tends constantly to turn the disk or wheelx-irrone direction. For turning the disk or wheel in the opposite direction, I provide a pull the back of the device. By pulling upon .the cord 34, the diskor wheel maybe rotated ina direction 1 to. wind .up the spring.

The free end of the, actuatingarm 6:.forthe thumb is connected to thedisk orxwheelby a link 36, oneend of which isxpivo-tally,connected, to .the

wheel or disk near the periphery of the. latter.

,The actuating arm 18:f0r the fingers extends rearwardly; far'enough' to overlapand .lie beside qthewheel or disk. In this-arm is a long slot. 37

extending l gthwise of the arm. On the whee1l11 .ordisk -isya-pin 38 projecting laterallyfrom;a

point near the periphery through the slotqin the ,armll8. Therefore, when the disk or wheelris prefer to providethe .bar.15 with a long-bearing To this end I, have fixed the bar 15 to a short sleeve 1'7 that fits rotatably upon the member 12. .The b3.I;l4=:.-l11' the second finger is extended rearwardlyto: formzanxoperatingxarm or lever 18.

The finger unit is so proportionedathat, when its base or rear end. is inserted in;.the; open front end of the palm device, the;tub.ular;member12 fits between thickened parts20 andr2l;onltheside walls of the palm-device. .A long pin. or screw, extending through the parts :20 and 321 :and through the interior of the tubular;member.12,

serves to secure the finger unit. to the palm .device, while permitting it toswing OPI'OCk'FfizbOllti an axis parallel to the hinge axisofthe thumb. In the arrangement shown, the. pin is, in the form; of a long screw. boltv 22, whosehhead'. :fits. intorai socket I or recess on'the outer face of the thickened part 20 of the palm device, and whose'screwi-threaded end is screwedinto the thickenedrpart..2lrat the opposite edge or side of the palmqdeyice.

thedirection in which the wheelis turned. in the arrangement illustrated in the main views-of the drawings, the springturns the wheel or-diskwin thedirection to openthe hand, whereas the pull cord-turns the .wheel or disk the direction-to close the hand. In other words, the stren thpf the final grip, when the hand is closed uponan ,object, depends upon the power applied to the :pull cord. In-this construction, thespringneed .be madeonly strong enough to, insure that the hand will open quickly when it is free to do so.

It, isdesirable that, after the, hand has closed upon .an object,it will maintain itsgrip without further attention .on the part of ,the wearer. .I. have, therefore, provided means for locking the thumb and fingers in. any one ofa varietyof positions. In the arrangementshown, this look- ,ing means consists simply of a pawl and ratchet.

Thus, as. best shown in Fig. 6, there is secured to one side of the disk or wheel. 25 a'toothed segment'40 with which cooperates a toothed pawl 41 having a stem .or finger piece 42 extending to'the exterior of'the hand through a hole 43 The .arms 6 and 18 lie .in parallel rplanes slightly separated. from each: other. hollow palm device, parallel with, "and between end passes through a stationary block or pedestal 27 that may be detachably held in place byscrews Within the I said, planes, isa' wheel or;;disk.;25::rotatable.;::on a

on-the under side. As best shown in Fig.17, the

the part 42 is shifted laterallyinto the short arm 44-of'the L, the-pawl is held away'ifrom the ratchet teeth so that the hand may be opened ratchet teeth and will lock-the hand against .opening until the pawl is tripped. Of course the vteeth of;the ratchet wheel cannot be made hole 43 is in the form of an L-shaped slot. When I sofinethat the handfifth fin ers were rigid, 11

"cover 'all' forms 'and"arrangements which come could be -locked soas to'maintain-a firm gripat each and every point inthe range ofclosing movements of the hand. 1 However, by making the thumband fingers of rubber and," particularly by leaving the finger tips without'mny internal stifiening'--means, the finger tips may yield' sufficiently after the hand hasclosed'on an object to insure that the pawl may catch a tooth and thus maintain the pressureof the fingers on the object. In other words, by permitting the fingers to yield sufiiciently to permit the disk or wheel to turn through an angular length, equal to one tooth after the thumb and fingers havecome into contact with an object, it makes no difference whether such contact is first made when the pawl is midway between two teeth or in any other position relatively to the teeth; because a pull on the cord will always permit the wheel or disk to be turned far enough to permit the pawl to snap into engagement with the next or following tooth. Furthermore, if the rubber is comparatively soft, the slight compression required of the tips of the fingers to permit the pawl properly to catch will not greatly increase the pressure on the object that is being held, although, if a very powerful grip is desired, the compression may, of course, be carried to a point Where the thrust will be directly resisted by the reenforcing bars in the thumb and fingers. In Fig. 8, I have shown the thumb and the forefinger holding between them an object A. It will be seen that both the thumb and the finger have been flattened to the extent indicated by the dotted line portions overlapping the area of the object A.

It will be seen that the pulling force of the cord is applied to the wheel or disk at the periphery, providing a comparatively long lever arm between the axis of rotation and the point at which the power is applied. Furthermore, the pin or stud 33 and the point of connection between the link 36 and the wheel or disk being near the periphery of the latter, the forces that are applied to open and close the hand are effectively transmitted. 1

Where it is desired to have the spring close the hand and the pull cord open the same, the spring and the pull cord are connected to the wheel or disk in such a manner that they act respectively in opposite directions from those in the construction heretofore described. Such a modified arrangement is shown in Fig. 9 from which it will be seen that the pull cord extends rearwardly from underneath the wheel or disk instead of from above. Furthermore, the spring 31a, corresponding to the spring 31 in the other form, is wound in the opposite direction from the spring 31. With this construction it is of advantage to be able to increase the tension of the spring in case it should weaken; this being made possible by the insertion of a key through the hole 39 as heretofore explained. By making it possible to wind up the spring after it has been assembled in the hand, it becomes a simple matter to set the unit, composed of the shaft 26, the wheel or disk and the spring, into the hand and then wind up the spring.

In order to give access to the interior of the palm device, I form in the back thereof a large thus illustrated and "described; but intend to within'the definitions of my invention constituting the appended'claims.

- I claim:

' 1.- A finger unit for an artificial hand comprising a single body of soft rubber in the form of four fingers joined together at the knuckles by a transvers'ebase member, a reenforcing bar within and extending lengthwise of said base member,-lon'g,'-stiif reenforcing elements embedded in and extending lengthwise of said fingers, a hinge connecting one of said elements to said rod, and the other elements being fixed to said rod.

2. A finger unit for an artificial hand comprising a single body of soft rubber in the form of four fingers joined together at the knuckles by a transverse base member, a reenforcing bar within and extending lengthwise of said base member, long, stiff reenforcing elements embedded in and extending lengthwise of said fingers, a hinge connecting the reenforcing element in the third finger to said rod, and the other elements being fixed to said rod. I

3. A finger unit for an artificial hand comprising four fingers and a base joined to the fingers at the knuckles, the whole being formed of soft rubber, a reenforcing bar extending transversely to the fingers through the base, fiat bars arranged on edge in said fingers and extending lengthwise thereof from said reenforcing bar, a hinge between one of the bars in the fingers and the said reenforcing bar, and the other bars in the fingers being fixed to the reenforcing bar.

4. In an artificial hand, a hollow palm device, a member extending across the front end of said device and connected thereto for rocking movements about an axis transverse to said device, fingers projecting forwardly from said member, a thumb connected to said device for rocking movements about an axis parallel to the aforesaid axis, a disk mounted in said device for turning movements about an axis parallel to the aforesaid axes, a'spring tending constantly to turn said disk in one direction, a cable fixed at one end to the disk and extending circumferentially thereof and then tangentially therefrom to turn said disk in the opposite direction, a slotted lever arm fixed to and extending from said member at right angles to the first-mentioned axis to a position beside the disk, a pin on the disk engaged in the slot in said lever arm, a lever arm fixed to said thumb, and a connecting rod extending between the latter lever arm and the disk.

5. In an artificial hand, a hollow palm device, a member extending across the front end of said device and connected thereto for rocking movements about an axis transverse to said device, fingers projecting forwardly from said member,

a thumb connected to said device for rocking movements about an axis parallel to the aforesaid axis, a disk mounted in said device for turning movements about an axis parallel to the aforesaid axes, a clock spring tending constantly to turn said disk in one direction, a flexible pull member connected to and extending circumferentially of the disk to turn the disk in the opposite direction, a slotted lever arm fixed to and extending from said member at right angles to the firstmentioned axis'to a position beside the disk, a.

pin on the disk engaged in the slot in said lever arm, a lever arm fixed to said thumb, and a connecting rod extending between the latter lever arm and the disk.

6. In an artificial hand, a hollow palm device,

1 device and connected theretoforvrocking move- ..movements about an axis parallel tolthesaforefixed at one end 'to thedisk and atuthe other end a member extending-acrossthe frontaendof said stoithe sshaft a releasable device to, lock the shaft against rotation, one end of the shaft being shaped to. receive aikey to turn the, same when released, a:pu1l:cord connected toiand extending circumments aboutran axis transverse to. said. device, fingers projecting forwardly fromsaid member, a thumb connected to said device for:rocking tion to the spring; and connections between said .memberand thumb and said disk to cause the hand toclose andopenas said element is turned first in one direction and .then in the other.

said axis, a shaft mounted in said device fon turn ing movements; about anax-is parallel to the aforesaid axes, a disk surrounding. and loose on said shaft, a clock spring surroundingsaid. shaft and FREDERICK CHARLES HENNING.

tferentially of the disk to turn the disk in opposii 

